July 2011

CP experts assess evidence for use of orthotic devices

Photo courtesy of Allard USA.

Despite progress, research gaps remain

By Larry Hand

The January publication in NeuroRehabili­tation of the recommendations from a consensus conference held in 2008 paints a less-than-perfect picture of the evidence underlying orthotic management of cerebral palsy (CP).

The conference did reach a consensus that ankle-foot orthoses (AFOs) can improve gait in ambulant children with CP, while the extent to which AFOs can prevent deformities remains unclear. However, as described in the January review, inadequate reporting and lack of transparency has compromised much of the published research, particularly regarding the types of patients and the design of the interventions being evaluated.

Now that nearly three years have elapsed since the conference, has the picture gotten any sharper?

“It’s too early to say, especially given the paper we are discussing was published only in 2011. Any improvement in the quality of research methodology and reporting is likely to be slow,” said first author Christopher Morris, MSc, DPhil, senior researcher in child health at Peninsula Medical School in Exeter, U.K. “Two key methodological improvements would be longitudinal design, long-term follow up, and increasing the number of subjects in studies.”

Yet others say progress has been made.

“At the time I agreed with the assessment,” said Bob Lin, CPO, chief orthotist for Hanger Orthopedic Group at Children’s Medical Center in Hartford, CT. “Now I think we’re turning the corner relative to better outcome measures in bracing. One of the biggest things is better use of computerized gait analysis for pre- and postoperative management. We can look at certain metrics, such as step length and muscle firing, and we can compare these to normal gait parameters or certainly pre-brace gait parameters. As opposed to the [formerly] very rare instance where one would have an ambulatory CP patient walk through a motion lab and be assessed for the effects of the brace on gait, it’s becoming more prevalent now.”

The September 2008 conference, held in Oxford, U.K., and sponsored by the International Society for Prosthetics and Orthotics, included 24 experts on a range of topics related to CP management, while the January paper focused specifically on orthoses. A summary of the conference proceedings, published in 2009, is avail­able online at: http://ispoint. org/images/ docs/publications/ispo_cp_report.pdf.

The limitations of published research on CP and orthoses do not necessarily reflect poorly on clinical practice, Morris noted, but patients and their families may not understand that.

“Clinicians should be aware of the prevailing uncertainty around whether treatments they are prescribing and providing have been shown to be effective, and discuss this with families,” Morris said. “Clinical trials are not necessary for all treatments, especially when an effect is immediately apparent or common consensus suggests that orthotic intervention is advisable. In other instances there is ample scope for research, especially with new orthoses that are not widely available, as is the case with Lycra-based orthoses.”

The review authors did a good job outlining one of the biggest controversies among clinicians who treat children with CP: whether to use an articulated or solid system, said Brigid Driscoll, CO, PT, at Children’s Memorial Hospital in Chicago. The review cited studies showing that solid AFOs can help increase the second peak of ground reaction force (GRF) in the propulsive phase of gait. They also cited new evidence suggesting that solid AFOs tuned to adjust sagittal plane alignment can improve the devices’ impact at proximal joints and on children’s gait.

“I definitely lean toward using the solid AFO, where you’re using the fine-tuning method, adjusting the shank angle and having a slight forward inclination to get optimal alignment at the hips and the knees,” Driscoll said. “Research needs to better define which exact AFO device we should use, what type of shoe we’re fine tuning, and the angle of inclination. We also need research to help us decide when that articulated system is going to be appropriate without compromising any of the biomechanical aspects of the foot and ankle.”

Today’s orthotist is better able to define or quantify outcomes, Lin said, a trend that is gradually rendering the ISPO report’s conclusions less accurate.

“Orthoses in general have become part of the standard treatment for CP,” he said. “An orthosis stabilizes the joint so that the patient, rather than having to do that with their own musculature or balance, no longer has to. Strategic bracing of a particular joint will then enable the therapist to work on mobilization of other joint mechanics and improve things like weight shift and balance reactions.”